Introducer sheath with braided filament securement mechanism

ABSTRACT

A tubular body for a medical device for insertion within a body passageway of a patient. The tubular body includes a tubular inner liner. A braided member is disposed along an outer surface of the liner. The braided member includes intersecting filaments and cells defined by the filaments. A securement mechanism, such as radiopaque solder, is disposed along a circumferential region of the braided member. The securement mechanism is attached to portions of the filaments and spans the cells that correspond to the circumferential region to inhibit relative movement of filament ends. An outer surface of the securement mechanism is sized to extend radially outward to a position up to an outer surface of the braided member to not add to the overall wall thickness of the tubular body. An outer jacket is positioned longitudinally around the braided member and connected to the inner liner.

This application claims priority to U.S. Provisional Application No.61/508,350, filed Jul. 15, 2011, which is hereby incorporated byreference herein.

BACKGROUND

This present disclosure relates to the field of medical devices, andmore particularly, to devices such as sheaths, catheters, or tubes witha mechanism to secure a braided filament.

Numerous advances of considerable note have occurred in medical surgicaltechniques over the last few decades. Among the most significantadvances has been the adoption, and now-routine performance, of a widevariety of minimally invasive procedures. Non-limiting examples of suchprocedures include angioplasty, endoscopy, laparoscopy, and arthroscopy.These minimally invasive procedures can be distinguished fromconventional open surgical procedures in that access to a site ofconcern within a patient is achieved through a relatively smallincision, into which a tubular device (or tubular portion of a device)is inserted or introduced. The tubular device, or device portion, keepsthe incision open while permitting access to the target site via theinterior (i.e., lumen) of the tubular device. Body passageways in whichmedical interventional devices are now commonly introduced include theesophagus, trachea, colon, biliary tract, urinary tract, and vascularsystem, among other locations within the body. One particularlysignificant example of a minimally invasive technique involves thetemporary or permanent implantation of a medical interventional device,such as a stent, into a passageway in the body of a patient.

When placing the medical interventional device, communication with thepassageway is typically attained by inserting an access device, such asan introducer sheath, into the body passageway. One typical procedurefor inserting the introducer sheath is the well-known Seldingerpercutaneous entry technique. In the Seldinger technique, a needle isinitially inserted into the passageway, such as a vessel, and a wireguide is inserted into the vessel through a bore of the needle. Theneedle is withdrawn, and an introducer assembly is inserted over thewire guide into the opening in the vessel.

Typically, the introducer assembly includes an outer introducer sheath,and an inner dilator having a tapered distal end. The tapered end of thedilator stretches the opening in the vessel in controlled fashion, sothat introduction of the larger diameter introducer sheath may then becarried out with a minimum of trauma to the patient. Followingsatisfactory placement of the introducer sheath, the dilator is removed,leaving at least the distal portion of the larger diameter introducersheath in place in the vessel. The interventional device, such as anexpandable stent, etc., may then be inserted through the introducersheath for placement at a target site within the vasculature.Alternatively, the stent may be placed at the target site by withdrawingthe introducer sheath from around the constricted stent. In eithertechnique, upon placement at the target site, the stent expands to thediameter of the vessel.

Historically, percutaneous insertion techniques were problematic, due atleast in large part to the lack of flexibility and/or kink resistance ofthe sheath. Early sheaths were typically formed of a relatively stifffluorocarbon, such as polytetrafluoroethylene (PTFE) or fluorinatedethylene propylene (FEP). The sheaths were typically of thin-walledconstruction, and were prone to kinking, particularly when threadedthrough tortuous pathways within the body. Increasing the thickness ofthe sheath only minimally improved the kink resistance of the sheath. Atthe same time, the added thickness occupied valuable space in thevessel, thereby minimizing the diameter of the interventional devicethat could be passed therethrough. In addition, increasing the thicknessof the sheath necessitated the use of a larger entry opening than wouldotherwise be required.

A kinked sheath is essentially unusable, and generally cannot bestraightened while positioned in the body of the patient. Consequently,once a sheath kinks, the sheath must be removed from the vessel, leavingan enlarged, bleeding opening which cannot generally be reused. Accessto the vessel must then be re-initiated at an alternative site, and theprocess repeated with a new sheath. In some cases, a suitablealternative site is not available, and the percutaneous procedure mustbe abandoned altogether in favor of a different, and often moreintrusive, technique.

In recent years, introducer sheaths have been improved in order toenhance their flexibility and kink resistance. Such sheaths are nowroutinely used to percutaneously access sites in the patient's anatomythat previously could not be accessed with existing sheaths, or thatcould be accessed only upon the exercise of an undesirable amount oftrial and error, with the concomitant discard of sheaths whose placementhad been unsuccessful.

Many newer sheaths exhibit a much higher degree of kink resistance thanwas achievable with prior art sheaths. One example of a flexible, kinkresistant introducer sheath is described in U.S. Pat. No. 5,380,304(“the '304 patent”), which is incorporated herein by reference in itsentirety. Here, the sheath described therein includes a lubricious innerliner having a helical coil fitted over the liner. An outer tube isconnected to the outer surface of the liner through the coil turns. Thecoil reinforcement imparts kink resistant to this thin-walled sheaththrough a wide range of bending.

Another example introducer sheath is described in U.S. PatentPublication No. 2001/0034514 (“the '514 Publication”), which isincorporated herein by reference in its entirety. The sheath describedtherein is similar in many respects to the sheath of the '304 patent,and is formed such that the proximal end of the sheath has a higherstiffness, while the distal end has a lower stiffness. Since the distalend of the sheath has a lower stiffness (and therefore is more flexible)than the proximal end, the sheath is able to traverse portions of theanatomy that would have been difficult, if not impossible, to traversewith stiffer sheaths. Since the proximal end has a higher stiffness (andis therefore less flexible) than the distal end, the sheath maintainsthe trackability to traverse tortuous areas of the anatomy. Thispresence of the coil reinforcement also enables this sheath to be kinkresistant through a wide range of bending angles.

Unfortunately, sheaths having a coil can exhibit poor pushability due toaxial stretching or compression and exhibit poor torqueability duringuse. To enhance torqueability and pushability, some introducer sheathshave included a braid, as well as a braid and a coil in the wall of itsshaft. Such construction of the sheath is described in U.S. PatentPublication No. 2002/0032408 (“the '408 Publication”), which isincorporated herein by reference in its entirety.

Notwithstanding the benefits that have been achieved by the use of suchintroducer sheaths, new challenges continue to be faced. For example,during manufacturing of the introducer sheath with a braid, the ends offilaments that define the braid can fray open and poke through the outerlayers of the introducer sheath. The ends may also extend inward andpoke through the inner liner into the passageway of the sheath. In someinstances, the braid filaments will tend to unravel duringmanufacturing. Consequently, the current processes for controlling thefraying of the braid, such as annealing, still results in manymanufacturing rejects.

It is desired to provide an improved introducer apparatus suitable fortraversing tortuous passageways in the patient's anatomy, and that iscapable of minimizing the problems of the prior art. More particularly,it is desired to provide a braided member configuration within anintroducer sheath that is capable of minimizing fraying of the braidend, thereby reducing manufacturing rejects. It would be desirable toreduce the fraying of the braid end without contributing additionalthickness to the sheath wall to ensure the sheath wall is as thin aspossible.

BRIEF SUMMARY

The problems of the prior art are addressed by the features of thefollowing examples. In one form thereof, a tubular body for a medicaldevice can include a tubular inner liner and a braided member. Thebraided member can be disposed along the outer surface of the innerliner. The braided member can have a proximal end and a distal end, andcan include a plurality of intersecting filaments and a plurality ofcells defined by the intersecting filaments. The braided member can havea braided filament securement mechanism disposed along a circumferentialregion located at the distal end of the braided member. The securementmechanism can be configured to inhibit relative movement of filamentends. The securement mechanism can be attached to portions of thefilaments to span the cells that correspond to the circumferentialregion. The outer surface of the braided member is positioned at orbeyond the outer surface of the securement mechanism. An outer jacketcan be positioned longitudinally around the braided member to connect tothe inner liner. In one aspect, the securement mechanism includes aradiopaque solder material. In another aspect, multiple circumferentialregions can include the radiopaque solder material, where thecircumferential regions are axially spaced from one another at regularintervals.

In another form thereof, an introducer sheath includes an inner liner, abraided member, and a coiled member. The braided member can be disposedalong the outer surface of the inner liner. The braided member caninclude a plurality of intersecting filaments and a plurality of cellsdefined by the intersecting filaments. A braided filament securementmechanism can be disposed along a circumferential region of the braidedmember and configured to inhibit relative movement of the ends of thefilaments. The thickness of the securement mechanism is sized to fitbetween the outer and inner surfaces of the braided member. Thesecurement mechanism can include a radiopaque solder that is rigidlyfused to portions of the filaments and spans the cells that correspondto the circumferential region. The coiled member can be disposed alongthe outer surface of the inner liner. An outer jacket can be positionedlongitudinally around the braided member, and connected to the innerliner. In one aspect, the securement mechanism can be disposed along adistal region of the sheath, which is movable between an arcuateconfiguration and a linear configuration.

In yet another form thereof, a method for manufacturing a tubular bodyfor a medical device is provided. The method can include one or more ofthe following steps. A solder can be applied to a circumferential regionof a braided member for an axial length. The braided member can includea plurality of intersecting filaments and a plurality of cells definedby the intersecting filaments. The solder can rigidly fuse portions ofthe intersecting filaments and can span the cells. The outer surface ofthe solder is sized to extend radially outward to a position up to anouter surface of the braided member. The braided member can bepositioned over at least a portion of an inner liner tube. An outerlayer jacket can be secured over the inner liner tube and the braidedmember. Portions of the solder can be removed so that the outer surfaceof the braided member extends at least beyond the outer surface of thesolder.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view, partially in section, of an example medicaldevice;

FIG. 2 is a partial longitudinal cross-sectional view of a partialportion of the wall of the medical device of FIG. 1;

FIG. 3A is a partial longitudinal cross-sectional view of a partialportion of the wall of another example medical device with a braidedfilament securement mechanism;

FIG. 3B is a partial side view of an end of another example medicaldevice during its construction;

FIGS. 3C-3D illustrate the relative thickness between the braidedfilaments and the example braided filament securement mechanism;

FIG. 4 is a side view of a braided member disposed over a mandrel,depicting an example application of a braided filament securementmechanism;

FIG. 5 is a side view of the braided member disposed over the mandrel ofFIG. 4, depicting an example cutting operation of a braided filamentsecurement mechanism;

FIG. 6 is a side view of the braided member disposed over the mandrel ofFIG. 5, depicting an example removing operation of a braided filamentsecurement mechanism;

FIG. 7 is a side view of a braided member disposed over a mandrel,depicting a plurality of braided filament securement mechanisms along abraided member; and

FIGS. 8-11 are side views of exemplary method steps used to manufacturethe medical device of FIG. 1.

DETAILED DESCRIPTION OF THE DRAWINGS AND THE PRESENTLY PREFERREDEMBODIMENTS

For the purposes of promoting an understanding of the principles of theinvention, reference will now be made to the embodiments illustrated inthe drawings, and specific language will be used to describe the same.It should nevertheless be understood that no limitation of the scope ofthe invention is thereby intended, such alterations and furthermodifications in the illustrated device, and such further applicationsof the principles of the invention as illustrated therein beingcontemplated as would normally occur to one skilled in the art to whichthe invention relates. It is understood that like-referenced numeralsare used throughout the Figures to designate similar components.

In the following discussion, the terms “proximal” and “distal” will beused to describe the opposing axial ends of the inventive apparatus, aswell as the axial ends of various component features. The term“proximal” is used in its conventional sense to refer to the end of theapparatus (or component thereof) that is closest to the operator duringuse of the apparatus. The term “distal” is used in its conventionalsense to refer to the end of the apparatus (or component thereof) thatis initially inserted into the patient, or that is closest to thepatient during use.

In FIG. 1, an example medical device 10 useful for performing any of avariety of minimally invasive medical procedures, including angioplasty,diagnosis, chemotherapy, drainage, endoscopy, laparoscopy, arthroscopy,and the guiding or introduction of other devices into a patient isillustrated. In its simplest form, the medical device 10 is a simpleguide, diagnostic, infusion or drainage catheter or introducer sheath,which will be referred to throughout the specification as an introducersheath 12.

The introducer sheath 12 includes a tubular sheath body 11 having apassageway 13 that extends longitudinally therethrough. The tubular body11 includes a proximal portion 15, and a distal portion 17 for initialinsertion into the body passageway. In the non-limiting embodimentshown, the end of the proximal portion 15 of the tubular body 11 isreceivable in a base structure 19. Those skilled in the art willappreciate that the base structure 19 can include various conventionalproximal attachments, such as a hub assembly or a multi-chambermanifold.

FIGS. 2-3A are longitudinal cross-sectional views of a partial portionof differently constructed tubular sheath walls. These figures bestillustrate the layered structure of the sheath wall, and the relativepositions of one or more reinforcing members. Two reinforcing members,namely a coiled member 14 and a braided member 16, are disposed along atleast partially the length of the body 11 in a manner to be described.If desired, a conventional radiopaque marker band 21 may be incorporatedinto the distal end 17 of the sheath in well-known fashion.

The coiled member 14 may comprise a medical grade metal or metal alloy,such as stainless steel, or a shape memory composition such as nitinol.Alternatively, the coiled member 14 may be formed from other medicalgrade materials known in the art to be suitable for such use, such aspolymers and composite materials. In one example, the coiled member 14is formed from flat wire as shown in FIG. 2, although a coiled memberformed from other compositions and having other cross-sections such ascircular or elliptical may be substituted in an appropriate case. Asdescribed herein, the coiled member 14 may be wrapped, wound,compression fitted, or otherwise applied around an inner liner, ifemployed, in conventional fashion. In one example, the coiled member canbe in a stressed, radially expanded condition, such as described in thepreviously incorporated '408 Publication. Coils are well-knownreinforcements for medical devices, and those skilled in the art arewell aware of other suitable techniques for applying a coiled member toa tubular member for medical applications.

The braided member 16 may extend over (FIG. 2) or under (FIG. 3A) atleast part of the coiled member 14. The braided member 16 comprises aplurality of intersecting filaments 22 of circular, flat, elliptical, orother conventional wire cross-section (circular being illustrated inFIG. 2). The braided member 16 can be formed of medical grade metal ormetal alloy. Non-limiting examples of such materials include stainlesssteel, shape memory alloys such as nitinol, a nickel-titanium alloy, orprecious metals such as gold and silver. Those skilled in the art willappreciate that the braided member 16 may alternatively be formed ofother medical grade materials known in the art to be suitable for suchuse, such as polymers and composite materials. The braided member 16 maybe formed with varied numbers and pitches of intersected filaments,which the number of filaments and pitch may be varied within segments ofa particular sheath, all in accordance with known techniques. As withcoiled members, the braided members are also well-known reinforcementsfor medical devices, and those skilled in the art are well aware ofsuitable techniques for applying a braided member to a tubular memberfor medical applications.

Although braided and coiled members are now routinely used asreinforcements in tubular medical devices, those skilled in the artrecognize that these reinforcements are not generally consideredinterchangeable. Rather, each is generally preferred in order to addressa particular condition likely to be encountered by the sheath duringintroduction into a body opening. For example, a coiled member istypically utilized in a sheath to minimize the possibility of the sheathkinking and/or to minimize ovalization of the sheath lumen duringbending of the sheath. The braided member, on the other hand, istypically utilized when it is desired to impart stiffness, pushability,and/or torqueability to the sheath. Such properties are advantageouswhen maneuvering a lengthy sheath into remote anatomy. A braided member,however, is not generally capable of providing the type of kinkresistance available with a coiled member. Similarly, a coiled member isnot generally capable of providing the type of pushability ortorqueability available with a braided member. Although each of thesetypes of reinforcements has its advantages as described, the ability toresist kinking and ovalization throughout a large bending radius isoften considered a paramount property of a sheath. This is particularlytrue in the vicinity of the distal end of the sheath. For this reason,it is believed that most presently-available commercial introducersheaths include a coil reinforcement. Examples of such sheaths havingcoil reinforcements are described in the incorporated-by-referencepatent documents recited hereinabove. Since the proximal portion canhave a higher stiffness (and therefore less flexible) than the distalportion, the sheath maintains the trackability to traverse tortuousareas of the anatomy.

According to FIGS. 2-3A, the body 11 can include a polymeric outer layerjacket 18 positioned over and contacting the coiled member 14, thebraided member 16, or both. The outer layer 18 can maintain the coiledmember 14 in its position, such as, e.g., in a stressed, radiallyexpanded condition, by adhesion to the coiled member 14, for example, bythermally bonding to the coiled member 14. In one example, the outerlayer 18 may be formed of any well-known polymer commonly used for suchpurpose. In one example, the outer layer 18 comprises a heat formablepolyamide material, such as nylon, a polyether block amide (PEBA), orpolyurethane. This heat formable material melts upon heating, such thatportions flow between the respective cells of the braided member or theturns of the coiled member, and bond to the outer surface, which ispreferably roughened, of an inner liner, if employed.

Any particular portion of the tubular body 11 can be given a flexibilityor springiness which is different from the flexibility or springiness ofthe remainder of the body 11. There are several ways in which thisdifference can be achieved. In one example, the thickness of the outerlayer 18 can be varied along the length of the body 11. In anotherexample, the outer layer 18 can be formed from at least two discretelongitudinal segments (such as the proximal segment 28 and the distalsegment 30) of differing durometer. Making the distal segment 30 of theouter layer 18 from a softer material than that from which the proximalsegment 28 is made yields a tubular body 11 that has a more flexible orspringier tip than the balance of the body 11. In another example, thecoiled member may extend distally beyond the distal end of the braidedmember or vice versa. This leaves a distal portion of the coiled memberor braided member, which is not covered by the other of the braidedmember or coiled member, and similarly yields a tubular body having amore flexible or springier tip than the balance of the sheath body.

In FIGS. 2-3A, the tubular body 11 may include an inner liner 20.Without regard to whether the tubular body 11 comprises the inner liner20, the body 11 has the passageway 13 extending longitudinallytherethrough. The passageway 13 can receive a conventional guide wire(not shown) therein, or the passageway 13 can be intended for thedelivery of a diagnostic or therapeutic fluid, or the removal of a fluidfrom the patient.

The inner liner 20 may be beneath and in contact with at least part ofthe coiled member (FIG. 2) and/or the braided member (FIG. 3A). Theinner liner 20 can include a lubricious material to allow for easyinsertion and withdrawal of the medical interventional device, and morepreferably, a fluoropolymer of the type commonly used to impart strengthand lubricity to a medical device. Most preferably, the fluoropolymercomprises polytetrafluoroethylene (PTFE). Lubricious inner liners forsheaths are well known in the medical arts, and those skilled in the artcan readily select an appropriate liner for a particular use. The innersurface of the inner liner 20 can also be smooth and nonporous forminimizing the formation of blood clots and other thrombi thereon. Thewall of the inner liner 20 may have sufficient radial rigidity toprevent the filaments of the braided member 16 and/or the turns of thecoiled member 14 from protruding into the passageway 13.

It is envisioned that the inner liner can have a uniform inside diameterranging up to about 30 French (10 mm), or even higher in some instances,thereby allowing passage of the largest possible diameter medicalinterventional device therethrough. The wall thickness of the innerliner will typically range between about 0.001 and 0.003 inch (0.0254and 0.076 mm), and is preferably about 0.0015 inch (0.038 mm). Evenlarger, or smaller, wall thicknesses may be appropriate in a particularcase. Those skilled in the art will appreciate that all dimensionsrecited herein are exemplary only, and that the apparatus describedherein may be constructed to be of any size necessary and appropriate toaccomplish the purposes for which the sheath is to be employed.

As shown in FIG. 1, in one example the sheath can have a distal tipregion 31 that is linear in form and that is elongate such as, e.g.,about 7 cm. A linear distal tip region can be especially suitable forvascular applications involving tortuous paths. To this end, the lineardistal tip region can be a flexible kink-resistant distal tip portionthat is preferably atraumatic. Also seen is the radiopaque marker band21 can be positioned about 0.25 inches from the end 17. FIG. 1illustrates another exemplary sheath having a distal tip region 33 thatis formed into an arcuate section (shown in dashed lines). The arcuatedistal tip region 33 may be formed by placing the fabricated sheathunder elevated temperatures while being constrained in a template ofappropriate curvature, such as at an angle of about 90 degrees, althoughother angles are possible. For example, a flexible kink-resistant distaltip portion of about 2.5 cm with such curvature is especially suitablefor use in entering the renal ostium and eases stress to the renalartery. In one example, the distal tip region is flexible to movebetween an arcuate configuration and a linear configuration.

Fraying of the end of the braided filaments is known to penetratethrough the outer layer and/or the inner liner, thereby producingunusable sheaths. To minimize the possibility of such fraying, thebraided member may be further processed before its application to themandrel. In one example, the braided member can be subjected to a heattreatment process, such as an annealing process, in order to inducesoftness or improved ductility to the braided member. A more relaxedbraided member reduces the risk of fraying during manufacturing.

According to FIGS. 3A-3B, the braided member 16 includes a portionhaving a braided filament securement mechanism 45 to address suchfraying. The securement mechanism 45 can fix the filaments 22 in asecured relationship relative to one another to facilitate the fixationof the ends of the braided member and prevent the ends from frayingoutward and/or inward. Portions of the securement mechanism 45 can spanand fill the open cells 23 that are defined by the intersecting braidedfilaments 22, as shown in FIG. 3B. Since the securement mechanism spansthe cells to attach to the adjacent intersecting filaments, the bondingbetween the intersecting filaments can be enhanced along the entiresegments of the filaments that define the corresponding cells. The outersurface 47 of the securement mechanism 45 can be sized to extendradially outward to a position up to, and preferably, not beyond, theouter surface 49 of the braided member 16 defined generally by thefilaments 22. In other words, the thickness 51 of the securementmechanism 45 can be less than to about equal to the general thickness 53of the braided member 16 between the inner surface 55 and the outersurface 49 of the braided member in order to not add to the overall wallthickness of the sheath. FIG. 3C illustrates one example where the outersurface of the securement mechanism 45 can form a generally smoothsurface with the outer surface of the braided member. Here, thethickness of the securement mechanism 45 within the cells 23 is aboutthe same as the thickness of the braided member, i.e., about twice thethickness of a single filament. FIG. 3D illustrates one example wherethe securement mechanism 45 can be thinner than in FIG. 3C. Here, thethickness of the securement mechanism 45 within the cells 23 is aboutthe same as the thickness of a single filament such that the combinedouter surfaces appear to have depressions formed therein at the centerof the cells. For instance, a single filament can have a diameter ofabout 0.0015 to about 0.002 inches.

The securement mechanism 45 can be applied at least partially along theentire circumference of the braided member. FIG. 3B depicts thesecurement mechanism 45 applied along the entire circumference of thebraided member to form a ring-like structure. However, the securementmechanism 45 can take on many forms and shapes, includingnon-geometrical shapes or patterns, zigzag pattern, or discontinuouscircumferential pattern. A zigzag or discontinuous pattern can beconfigured to provide additional flexibility to the distal tip.

The securement mechanism 45 may include any suitable material, includingbut not limited to solder, thermoplastics, such as those in the nylonand urethane families, adhesives such as cyanoacrylate, or a polymer,such as PTFE, for manufacturing purposes explained further below. Thesecurement mechanism 45 can include a radiopaque material to enhance itsvisibility under fluoroscopy or other imaging techniques. Nonlimitingexamples of radiopaque materials include silver, gold, platinum,tantalum, or various forms of derivate alloys thereof.

According to FIG. 4, after the braided member 16 is formed, the braidedmember 16 can be fitted over a mandrel 110 that is operable to maintainthe overall rounded shape of the braided member. The mandrel 110, whichis typically metal, can have a coating 112, such as a PTFE coating, toensure nonadhesion between the braided member 16 and the mandrel 110during application of the securement mechanism 45. The securementmechanism 45 can be applied to the braided member 16 using any suitabletechniques, including spraying the securement mechanism material ontothe braided filaments or dipping the braided member into a batch of thesecurement mechanism material. In accordance with one aspect, at thelocation where the securement mechanism will be formed, the braidedmember may be at least temporarily held in place by a temporary bonding,such as an adhesive.

In a next step, at least a circumferential portion of the braidedfilaments are joined or bonded together at one or more of theintersections and the cells that are defined by the intersecting braidedfilaments to reduce relative movement between the braided filaments withrespect to one another. The bonding may be achieved in various manners,including but not limited to thermal, mechanical and chemicaltechniques. The bonding can result in braided filaments that are rigidlyfused together and can generally form a solid region.

In one example, a tube of fluorinated ethylene propylene (FEP) can beapplied around the end of the braided member. Prior to cutting thebraid, heat can be applied to the FEP tube to cause it to heat shrinkonto the end of the braided member. This is believed to allow for a moreeven cut, while also preventing the ends of the braided member fromfraying. After the FEP is removed, the braided member is slid over theinner liner and over the coiled member, if employed, at one side(proximal) of the mandrel.

In another example, the securement mechanism may comprise a polymerictube that is wrapped around the end of the braided member. A heatsource, such as convection, radiant, or radiofrequency heatingtechniques, can be used to melt the polymer material to flow within theopen cells of the braided member. If the securement mechanism materialcomprises a thermoplastic such as nylon, the nylon may melt when exposedto an appropriate temperature, for example, between 300-500 degreesFahrenheit, depending on the particular melting point of the material.The polymer material of the securement mechanism may be a higherdurometer material than the outer layer material in order to provide amore rigid engagement with the filaments. The polymer material of thesecurement mechanism may have a higher melting temperature than theouter layer material so that the securement mechanism does not re-meltfrom the temperatures necessary to melt the outer layer material. Thepolymer material may have filaments contained therein. The filamentmaterial can be a radiopaque material, such as tungsten or otherradiopaque materials described herein.

In another example, the filaments may be coated with a sufficient amountof a polymer or solder so that when heated, the polymer or solder fillsthe cells defined between the braided filaments and defines thesecurement mechanism. Examples of coated filaments are described in U.S.Patent Publication No. 2010/0016837 and U.S. Pat. No. 6,562,022, each ofwhich is incorporated herein by reference in its entirety.

In another example, the securement mechanism 45 comprises a soldermaterial. With reference to FIG. 4, the braided member 16 and themandrel 110 can be positioned adjacent to a soldering iron 120 having asupply of solder 122, such as a soft solder alloy composed of, e.g.,Silver-Tin, which is commercially available as All-State No. 430 fromESAB Welding (Atlanta, Ga.). The soldering iron 120 includes a heatedmetal tip 124 to which the solder supply 122 is coupled. The heatedmetal tip 124 supplies heat to the solder 126 that is supplied from thesolder supply 122 so that the solder 126 can flow out from the tip 124.A flux compatible with the materials of the braided filaments and thesolder may also be used to enhance the bonding of the filaments. As thesolder 126 is flowing, the braided member 16 and the mandrel 110 can berotated about the mandrel axis 130 in either direction, represented byarrows 132, to form a circumferential region and/or translatedlongitudinally along the axis 130 in either direction, represented byarrows 134, to form the axial length.

In FIG. 5, solidification of the solder forms the securement mechanism45. A cleaning agent can be applied to the soldered region in order toneutralize the flux. The rate of solder flow and the rate of rotationand translation of the braided member and mandrel relative to the solderiron can be controlled to ensure that solder fills the cells 23 definedbetween the intersecting filaments 22 for a sufficient longitudinaldistance 140 suitable for fluoroscopic visualization, such as about 3-5mm, when the solder is a radiopaque material. In effect, the end of thebraided member may be less inclined to fray open or flare in a radiallyoutward and/or inward direction at the distal end of the braided memberdue to the securement mechanism. This feature may provide a significantadvantage during the manufacture of the introducer sheath.

It can be appreciated that the total length of solder can be at leasttwice the distance 140, or about 6-10 mm, so that the braided member canbe divided at the securement mechanism to form two braided segments. Forexample, in FIG. 5, a cutting instrument 148 can be applied to thebraided member and the securement mechanism, so that at least thedistance 140 is achieved. The cutting instrument 148, such as a blade orlaser, is configured to cut through the solder and the filaments. In thecase of a blade, the braided member and the mandrel are placed incontact with the blade and the braided member/mandrel is rotated aboutthe axis 130 relative to the blade in order to form the cut.

To minimize the wall thickness of the tubular body to as small aspossible, the profile of the braided member 16 with the securementmechanism 45 can be reduced by removing excess securement mechanismmaterial that extends beyond the general circumference of the outersurface of the braided member. For example, the outer surface of thesecurement mechanism 45 preferably does not extend beyond the outersurface defined by the filaments of the braided member 16 as describedherein. In FIG. 6, excess material of the securement mechanism may beremoved. For example, the braided member and the mandrel can be placedagainst a grinding instrument 150, such as a rotary grinding wheel thathas a grinding surface 152 for removal of the desired material. Forinstance, the securement mechanism can be viewed under magnification forvisual observation of the amount of remaining material. Preferably,under magnification the technician can observe portions of the outersurface of the filaments. Other grinding instruments can be used such asa metal file, sandpaper, or other devices that are known to removematerial.

In FIG. 7, the braided member 16 can include additional securementmechanisms, such as the securement mechanism 45A at other locationsbesides at the distal end 160 of the braided member 16. The additionalsecurement mechanisms can be spaced apart at regular increments forfluoroscopic indication of the insertion depth of the introducer sheath.Another application for the additional securement mechanisms is for themeasurement of the lesion or the problem area within the bodypassageway. The proximal end (not shown) of the braided member 16 mayalso include a securement mechanism as described above. However, it istypical that the proximal end of the braided member is fixed within ahousing of some sort such as a hub assembly, which remains outside thebody during its intended use and thus is less of a concern than thedistal end.

Referring now to FIGS. 8-11, exemplary method steps are described formanufacturing a medical device such as an introducer sheath. In FIG. 8,an inner tubular liner 20, if employed, may be placed over a mandrel200. The mandrel 200 has an outer diameter that is approximate orslightly less than a desired inner diameter of the inner liner. Thebraided member 16, with one or more the securement mechanisms 45 formedas described above, may then be cut to the desired size.

In FIG. 9, the braided member 16, with one or more securement mechanisms45 formed as described above, then may be advanced coaxially over theouter surface 205 of the inner liner 20 and mandrel 200. In oneexemplary technique, the mandrel 110 in FIG. 6, having the braidedmember 16 with the securement mechanism(s) disposed thereon, may bealigned with an end of the mandrel 200. The braided member 16 then maybe transferred from the mandrel 110 directly over the inner liner 20.The braided member 16 may be positioned such that the distal end 160 ofthe braided member 16 is positioned a short distance 201 (as shown inFIG. 3A) away from the distal end 207 of the inner liner 20, as shown inFIG. 7.

According to FIG. 10, the coiled member 14 may be fitted around thebraided member/inner liner/mandrel. Like the braided member 16, thedistal end 211 of the coiled member 14 may be positioned a shortdistance from the distal end 207 of the inner liner 20. The relativedistance from the distal end of the inner liner and the distal ends ofthe braided member and the coiled members may be same, as shown in FIG.10, or different. In one example, the distal end of the coil is fartheraway from the distal end of the inner liner. In another example, thedistal end of the coil is closer to the distal end of the inner liner.The coiled and/or braided members may also be positioned a shortdistance, the same or different distances, from the proximal end of theinner liner 20. FIG. 10 shows the turns of the coiled member 14 wrappedover the securement mechanism 45. When the coiled member is fitted overthe securement mechanism, the minimum thickness of the securementmechanism allows the coiled member to fit uniformly over the braidedmember and not flare out.

Advantageously, since the braided member 16 includes the securementmechanism 45 at the distal end thereof as described above, the ends ofthe filaments are less likely to fray open or to flare radially outwardand/or inward, which may facilitate insertion of the coiled member 14over the proximal end or distal end of the braided member 16. Theapplication of the securement mechanism 45 to the braided member 16 maysubstantially reduce or inhibit radial flaring at the distal end of thebraided member 16, after the distal end is cut to a desired length. Thisarrangement may facilitate retention of the braided member 16 at anouter diameter suitable for accommodating the inner surface of thecoiled member 14.

In FIG. 11, the outer tubular layer 18 then may be advanced coaxiallyover the reinforcement layers (braid and/or coil)/liner/mandrel. Theproximal and distal ends of the outer layer 18 may be substantiallyaligned with the proximal and distal ends of the inner liner 20,respectively, as generally depicted in FIG. 11. To this end, regions atthe proximal end and the distal end of the tubular body may not have anyreinforcement layer so the proximal and distal ends remain flexible topermit tapering and flaring of the ends of the introducer sheath. Oncein place, the outer layer 18 may be joined to the outer surface 205 ofthe inner liner 20, which preferably has been roughened, between thecells of the braided member 16 and turns of the coiled member 14.

The entire assembly is placed in a heat shrink envelope. Heat shrinkenclosures for use in forming medical devices are well known in the art,with FEP being a preferred composition for use herein. Those skilled inthe art will appreciate that various alternative compositions for theheat shrink envelope would also be suitable for use in forming thetubular body sheath, as long as the melt temperature of the materialused for the outer layer is lower than that of the heat shrinkenclosure. Heat may be applied at a suitable temperature that is withinthe processing temperature range of the outer tube material, such as,e.g., about 300-500 degrees Fahrenheit. In one example, the heat shrinkenclosure and contents are placed in an oven and heated (typically atabout 385° F. (196° C.) when FEP is used as the heat shrink and apolyether block amide is used as an outer layer material) for a suitableperiod of time to melt the outer layer material. This causes the outerlayer material to melt and flow between the cells of the braided member16 and the turns of the coiled member 14, being urged thereinto byshrinking of the heat shrinkable tube. The melted outer layer materialcan mechanically connect to the radially outer surface of the innerliner 20. The outer surface of the inner liner 20 may be chemicallyetched or mechanically roughened in well-known manner for enhancingbonding between the inner liner and the outer layer material. Afterremoval from the oven, the entire assembly is cooled, and the heatshrink envelope is cut away. Such a heat shrink technique is describedin greater detail in the '304 patent.

Once the process is completed, the heat shrinkable tubing may be splitfrom around the outer layer 18, the mandrel 200 may be removed fromwithin the lumen of the inner liner 20, and the tubular body is in theform shown from the partial side-sectional view in FIG. 1. Since theheat formable material of the outer layer 18 may also be self-leveling,it may provide a uniform outer diameter surface for the tubular body 11.Subsequently, other manufacturing steps may be employed to complete theconstruction of the introducer sheath 20, such as thermally bonding adistal tip portion to a distal end of the tubular body and/or a hubassembly to a proximal end of the tubular body, as generally set forthin the '304 patent and the '514 publication.

Various technical advantages may be achieved by placing the braidedmember 16 beneath the coiled member 14. For example, the surface area ofthe open cells between the filaments of the braided member 16 may begreater than the surface area of the open spacing between the turns ofthe coiled member 14, which may provide an increased surface area fordirectly bonding the outer layer 18 to the inner liner 20 during theheat shrink process. If the bond between the outer layer 18 and theinner liner 20 is enhanced, then the overall structural integrity of thetubular body 11 may be improved. Alternatively, the braided member 16may be disposed above the coiled member 14 and within the outer layer18, in which case it may be desirable to increase the spacing betweenturns of the coiled member to provide an increased area for directlybonding the outer layer to the inner tube liner. However, it will beapparent that the techniques described above to stabilize acircumferential section of filaments with a securement mechanism may beused in any sheath construction having a braided member, regardless ofwhether the coiled member is used in conjunction with the braidedmember.

Introducer sheaths may be formed to have any length required to fulfillits intended purposes. In most cases, the sheath will have a lengthbetween about 40 and 125 cm, and most generally, between about 70 and100 cm. Generally, the lengths of the inner liner 20 and the outer layer18 are the same. For an exemplary sheath of 70-100 cm length, the distalportion, for example the distal 30-60 cm, may be covered with aconventional hydrophilic coating, such as AQ® hydrophilic coating. Inaddition, if desired, the outer layer 18 can comprise two or morediscrete longitudinal segments of differing durometer. Making the distalportion of the outer layer from a lower durometer material than thatfrom which the proximal portion is made yields a tubular member whosedistal portion is more flexible than the proximal portion. Thisarrangement is described in greater detail in theincorporated-by-reference '514 Publication.

The dimensions (for example, the thickness) of the various elementsmentioned above should be selected in view of the proposed use of theintroducer sheath. It is believed that the selection of such dimensionswill lie within the level of skill in the art, once benefit of thepresent disclosure is had. While a modest amount of trial-and-error maybe needed to obtain optimal dimensions, it is believed that any requiredexperimentation will not be undue. Details of the construction orcomposition of the various elements of the introducer sheath nototherwise disclosed are not believed to be critical to the presentinvention, so long as the recited elements possess the strength ormechanical properties needed for them to perform as required. Many suchdetails not described herein are recited in detail in theincorporated-by-reference '304 Patent and the '514 Publication.Additional details of construction are believed to be well within theability of one of ordinary skill in the art.

In one example of use, a 4 to 8 French sized introducer sheath includesan arcuate distal tip region, a braided member, a coiled member, and asecurement mechanism formed from a radiopaque solder material such asshown in FIG. 3A. The distal end of such introducer sheath is initiallyinserted through a body opening previously formed, e.g., by thewell-known Seldinger technique. The introducer sheath is advanced,typically over a wire guide (not shown) through the body passagewayuntil the distal end reaches the target site. The distal end of the wireguide can then be retracted within the sheath so that the distal tipregion is permitted to assume its arcuate shape. The end user can thenmaneuver (i.e., applying torque to) the proximal end of the sheath sothat the distal tip region can be placed at a branching vessel, such asthe renal arteries. Once the distal tip is positioned within thebranching vessel, the wire guide can be advanced through the branchingvessel to the target site. Thereafter, the sheath can be moved along thewire guide to the target site within the branching vessel.

The tube can be configured for surgical use itself or can beincorporated into a device which also includes other apparatus havingsurgical utility. One example of the former is in a balloon catheter, inwhich the tube is configured (particularly shaped and adapted) as acatheter shaft carrying on it an inflatable balloon. Balloon cathetersare useful for performing angioplasty and for the deployment of a stentfor preventing stenosis (closure) of a body passage, e.g., a bloodvessel. Another example of the former is in a diagnostic, infusion ordrainage catheter, in which the tube is configured as a catheter for thedelivery of a diagnostic fluid to the patient (for example, forimaging); for the delivery of a therapeutic fluid to the patient (eithershort or long term); or for the removal of a fluid from the patient.Examples of devices including apparatus in addition to the tube areendoscopes, laparoscopes, arthroscopes or the like, and guide cathetersand introducer sheaths (percutaneous or otherwise), through which aguide wire or other surgical device is introduced into the patient.

It is therefore intended that the foregoing detailed description beregarded as illustrative rather than limiting, and that it be understoodthat it is the following claims, including all equivalents, that areintended to define the spirit and scope of this invention.

1. A tubular body for a medical device comprising: a tubular inner linerhaving an outer surface; a braided member disposed along the outersurface of the inner liner, the braided member having a proximal end anda distal end, and including a plurality of intersecting filaments and aplurality of cells defined by the intersecting filaments, the braidedmember comprising a braided filament securement mechanism disposed alonga circumferential region located at the distal end of the braided memberand configured to inhibit relative movement of the filaments, thesecurement mechanism attached to portions of the filaments and spanningthe cells that correspond to the circumferential region, wherein anouter surface of the braided member is positioned at or beyond an outersurface of the securement mechanism; and an outer jacket positionedlongitudinally around the braided member, and connected to said innerliner.
 2. The tubular body of claim 1, wherein the securement mechanismcomprises a radiopaque material.
 3. The tubular body of claim 1, furthercomprising a coiled member having a plurality of turns disposed over atleast a portion of the braided member and the inner liner.
 4. Thetubular body of claim 1, further comprising a coiled member having aplurality of turns disposed over the inner liner and underneath at leasta portion of the braided member.
 5. The tubular body of claim 1, whereinthe inner liner comprises a lubricious fluoropolymer.
 6. The tubularbody of claim 5, wherein the outer surface of the inner liner comprisesa roughened outer surface, and wherein the outer jacket is bonded to theinner liner at the roughened outer surface.
 7. The tubular body of claim1, wherein the securement mechanism comprises a radiopaque soldermaterial.
 8. The tubular body of claim 7, wherein the braided memberfurther comprises multiple securement mechanisms, the securementmechanisms being axially spaced from one another at regular intervals.9. The tubular body of claim 1, wherein the outer jacket comprises aheat formable polyamide material.
 10. The tubular body of claim 1,wherein distal ends of the respective outer jacket and inner linerextend distally beyond the distal end of the braided member to form anonbraided region in the tubular body.
 11. The tubular body of claim 1,wherein said securement mechanism comprises a polymer having filamentscomprising a radiopaque material.
 12. An introducer sheath comprising: atubular inner liner having an outer surface; a braided member disposedalong the outer surface of the inner liner, the braided member having aproximal end and a distal end, and including a plurality of intersectingfilaments and a plurality of cells defined by the intersectingfilaments, the intersecting filaments defining an outer surface and aninner surface of the braided member, the braided member comprising abraided filament securement mechanism disposed along a circumferentialregion of the braided member and configured to inhibit relative movementof filament ends, wherein the thickness of the securement mechanism issized to fit between the outer and inner surfaces of the braided member,wherein the securement mechanism comprises a radiopaque solder rigidlyfused to portions of the filaments and spanning the cells thatcorrespond to the circumferential region; a coiled member disposed alongthe outer surface of the inner liner; and an outer jacket positionedlongitudinally around the braided member, and connected to said innerliner.
 13. The introducer sheath of claim 12, wherein the securementmechanism is disposed along a distal region of said sheath, the distalregion being movable between an arcuate configuration and a linearconfiguration.
 14. The introducer sheath of claim 12, further comprisinga plurality of securement mechanisms axially spaced from one another atregular intervals.
 15. A method for manufacturing a tubular body for amedical device, comprising: applying solder to a circumferential regionof a braided member for an axial length, wherein the braided memberincludes a plurality of intersecting filaments and a plurality of cellsdefined by the intersecting filaments, wherein the solder rigidly fusesportions of the intersecting filaments and spans the cells, wherein anouter surface of the braided member is positioned at or beyond an outersurface of the securement mechanism; positioning the braided member overat least a portion of an inner liner tube; and securing an outer layertube over the inner liner tube and the braided member.
 16. The method ofclaim 15, wherein the applying step further comprises removing portionsof the solder so that the outer surface of the braided member extends atleast beyond the outer surface of the solder.
 17. The method of claim15, further comprising cutting the solder along the axial length toshorten the axial length of the solder.
 18. The method of claim 15,wherein the applying step further comprises applying solder to multiplecircumferential regions of the braided member.
 19. The method of claim18, wherein the multiple circumferential regions are axially spaced atregular intervals.
 20. The method of claim 15, further comprisingpositioning a coiled member over at least a portion of the inner linertube, wherein the securing step further comprises securing the outerlayer tube over the inner tube, the braided member, and the coiledmember.
 21. A method for manufacturing a tubular body for a medicaldevice, comprising: applying a securement mechanism of a first materialto at least an end of a braided member without applying the securementmechanism to an entire length of the braided member, wherein the braidedmember includes a plurality of intersecting filaments and a plurality ofcells defined by the intersecting filaments, wherein the first materialfuses portions of the intersecting filaments and spans the cells,wherein an outer surface of the braided member is positioned at orbeyond an outer surface of the securement mechanism; positioning thebraided member over at least a portion of an inner liner tube of asecond material; and securing an outer layer tube of a third materialover the inner liner tube and the braided member.
 22. The method ofclaim 21, wherein the first material is solder.
 23. The method of claim21, wherein the first material is an adhesive.
 24. The method of claim21, wherein the first material is applied to the braided member byspraying.